短语词组短語coal -gas-outburst 煤與瓦斯突出Keywords Coal -gas outburst 關鍵字煤與瓦斯突出preventing coal -gas outburst 防治煤與瓦斯突出gas -outburst coal 瓦斯突出煤Double -outburst coal seam 雙突煤層upgrade of non -outburst coal seam 非突出煤層陞級 返回 coal-outburst